Hydraulic drill jumbos an overview


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Hydraulic drill jumbos an overview

  2. 2. Background  In order to create an opening in a rock mass DRILLING is the basic requirement.
  3. 3. Range & Selection of Drill Jumbos ……….for every Tunnel section
  4. 4. Single Boom Jumbos
  5. 5. Two Boom Jumbos (8 - 45 sq.m.)
  6. 6. Two Boom with basket (8 - 90 sq.m.)
  7. 7. Three Boom/Three Boom with Basket Boom (upto 168 sq.m.)
  8. 8. Probing ahead
  9. 9. Drill Jumbo - Long Holes
  10. 10.  Optional equipment
  11. 11. Basic requirement for rock drilling
  12. 12. Rock Drilling - Principle Basic requirement :
  13. 13. Rock drill mechanism Impact The piston transmits the impact energy through the drill steel to the hole bottom. A valve directs the compressed air / hydraulic oil from one side to the other of the piston so that it moves up and down.
  14. 14. Impact
  15. 15. Rock drill mechanism Rotation The drill steel is turned lightly with each blow. IN PNUEMATIC ROCK DRILLS : The rotation is normally anti-clock wise and normally made on the return stroke of the piston. The theoretical angle of rotation per stroke is 36 degree. In practice it is 30 degree. The difference is due to mating part. IN HYDRAULIC ROCK DRILLS : Hydraulic motor is normally used for rotation. The rpm of the drill bit is adjusted as per drill bit diameter.
  16. 16. Rock drill mechanism Feed force The feed force is created by hand in case of hand held drills , Pusher leg or hydraulic cylinder. Proper feed force will give the best penetration rate. Improper feed force will cause:  Loosening / damaging of thread.  Overheating / low life of drill string.  Diverted hole / poor pull in blasting.
  17. 17. Rock drill mechanism Flushing Flushing is done normally by air or water on all the rock drills used in underground, water is used as flushing media. Optimum flushing will provide better penetration rate.
  18. 18. Factors which influence drilling rate        Type of rock Air pressure/Hydraulic Pressure Bit size Bit condition Flushing Feed force Wear of front of rotation chuck bushing
  19. 19. Drifter - Heart of Drilling Jumbo
  20. 20. New Generation Rock Drill
  21. 21. Components of Hydraulic Drifter Shank Adapter          Flushing Head Damping Piston Stroke Selector Piston Rotation Gears Cylinder Accumulators Hyd. Rotation Motor
  22. 22. Driver       Transmit rotation from Hyd. Motor to Shank Adapter Triangular in shaped Housed in rotation chuck Has internal splines Made of bronze/Steel Splines wear limit is half it original width.
  23. 23. Stop Ring     Serves as retainer for Shank Adapter Stop Ring is extremely hard and wear resistant It is subject to impact energy Wear limit is 1 mm to the front end of the splines
  24. 24. Damping Piston     Damping Piston protects the Rock Drill from shock waves (thru hydraulic pressure) Subject to powerful axial shock waves. It helps in absorbing reflex shocks upto 20 tonnes. Since it is pressed against rot.chuck/shank adapter, it tends to partially rotate.
  25. 25. Side Bolts    Two long side bolts hold together the external parts of the Rock Drill (front head, cover, gear housing, interm. part and cylinder Third long side bolts connect all above parts except front head. Two long side bolts have have integral eccentric lugs(for tightening)
  26. 26. Side Bolts    Tension of the side bolts must be checked regularly. Rear dome nuts are tightened as per the recommended torque Recommended to change both the bolts together.
  27. 27. Piston Guides    Front and Rear piston guides located on either end of the cylinder guides the lateral movement of the piston. It prevents the piston lands from touching the cylinder Its has wear resistant quality and also gives lowest possible friction.
  28. 28. Impact Piston     The piston strikes the shank adapter between 3000 – 3600 stokes per minute Piston is supported by piston guides. Slim piston design transfer optimum energy to the drill string Slim piston design also has low stress on Rock Tools
  29. 29. Rotation Chuck Sleeve   Rotation Chuck sleeve is a press fitted into the rear of the Rotation Chuck It is made of high quality bronze with high resistance to wear and friction
  30. 30. Rotation Chuck Bushing     The smaller front face of the Rotation Chuck bushing acts on the shank adapter. Larger rear face is subject to the thrust from the damping piston. Front face of the rotation chuck bushing is subject to steady wear. Max. permissible wear on the front face of the rotation chuck bushing is 1 mm.
  31. 31. Flushing Head
  32. 32. Rock Drill - Reflex Hydraulic Rock Drills normally work at 200 Bar Impact Pressure Every Impact of the Rock Drill  Generates 20 Ton Reaction / Reflex from Rock Reflex 20 Ton Drifter Impact
  33. 33. Drifter without Reflex Dampener
  34. 34. Reflex kills the Drifter & Mounting
  35. 35. Most effective Reflex Dampener
  37. 37. SAFETY REGULATIONS      Special attention must be paid to safety information and especially to the warning symbol (triangle). Never attempt maintenance of Rock Drill when the hydraulic system is pressurised Always use correct specification hoses, specially the impact hose of rating SAE 100 R9R/4SH/4SP (4 layers, spirally wound steel wire braided). Use protective plugs when dismantling the Rock Drill Always overhaul a Rock Drill in a Container or a clean workshop
  38. 38. Start Up   Before starting up a new or a newly overhauled Rock Drill:  Connect up all hydraulic hoses  Charge the Accumulators with Nitrogen gas to the correct pressure  Fill correct hydraulic and lubricating oil  Adjust correct lubricating system Tighten all threaded joints after first shift of operation
  39. 39. Every Shift     Check that Air & Lubricating oil come out between the shank adapter and front guide Check S/Adapter threads are not damaged Keep an eye on the hydraulic hose vibration. If they vibrate too much check the Accumulators. Check there is no leakage from the Rock Drill. If flushing water leaks from the hole in the front head, change the seals.
  40. 40. Every 40 Percussion Hour     Grease the Gear Housing Tighten all threaded joints as per specified torque. Check for external leakage on the Rock Drill. Replace the seals if leaking Check condition of hydraulic hoses, replace damaged/defective hoses.
  41. 41. Every 400 Percussion Hour  Recommended for complete overhaul.  Overhauling to be done in a clean and suitable workshop. Always use Hydraulic Drifter Repair Tools.
  42. 42. Accumulators Accumulators are fitted with safety labels  They should be charged with Nitrogen gas only (other gas can cause explosion)  All new accumulators are not charged 
  43. 43. Charging the Accumulators       Remove the protective plugs Open the valve nut and connect the charging hose Open the gas valve on the cylinder Charge the Accumulator to the collaring pressure minus 30 bar. However the maximum pressure should not exceed 110 bar Tighten the valve nut and also close the cylinder valve. Remove the charging hose and fit back the protective cap on the accumulator valve
  44. 44. Intake : 30 bar below collaring pressure Max - 110 bar Return : Not to be charged Accumulators Damping : 20-25 bar
  46. 46. Carrier
  47. 47. Power train
  48. 48. Carrier System CARE & MAINTENANCE
  49. 49. Engine – Air Filter 1.Clean every week 2.Change interval normally depends on environment
  50. 50. Engine – Oil & Filter Change interval depends on different factors: a. Quality of oil b. Working temp c. Environment
  51. 51. Engine – Fuel Filter Change interval normally depends on quality of fuel
  52. 52. Carrier Greasing Grease every week. Check once in every month whether grease is passing through every point
  53. 53. Drive line : greasing Grease every point once in a week. Only two stroke of grease is sufficient. Use good quality grease. Check bolt torque weekly
  54. 54. Coolant Level Check Coolant level daily
  55. 55. Transmission Oil & Filter Change interval depends on different factors: a. Quality of oil b. Working temp c. Environment
  56. 56. Transmission oil change A - Filling B - Drain C - Filter the oil when it is hot through drain plug “B”. e oil through port “A” up to “LOW” mark on dipstick. e the filter. he engine at low idle to fill up the converter and fill oil up to low mark. he engine to heat up the oil at 80 deg. C fill up to high level.
  57. 57. Differential Check level every week Change every 500 hours
  58. 58. Planetary hub Check level every week Change every 500 hours
  59. 59. Release Park brake Loosen lock nut “A” Screw in stud “B” to the bottom. To reset the park brake screw out the stud “B” to 47 mm. Tighten the lock nut.
  60. 60. Service brake adjustment Place the rig on jacks. Open the lock nut “A” & lock plate “B”. Unscrew the adjusting screw “C” anticlockwise to take up any play. Continue to turn until a torque of 40 Nm is attained. Now screw the adjusting screw “C” clockwise 3 turns. Refit lock plate “B” & lock nut “A”.
  61. 61. Hydraulic Booms
  62. 62. B A C
  63. 63. Cross cut drilling
  64. 64. Hydraulic Booms
  65. 65. Rotation unit
  66. 66. oom B Hydraulic Syst em
  67. 67. Cylinder movement - Vertical
  68. 68. Cylinder movement - Horizontal
  69. 69. a M e n i e t a n c n
  70. 70. Adjustment - Feed cradle
  71. 71. Cradle clearance adjustment
  72. 72. Replacement of guide rail
  73. 73. In Conclusion…. Drilling is the backbone of all mining & tunneling applications & thus the role of Electro Hydraulic Drill Jumbos assumes critical proportions. While these equipment are quite simple to operate with built in ling term reliability, optimization of drilling functions and high levels of availability is only possible if correct maintenance and operational directions are followed. The presenters of this paper thankfully acknowledge the assistance from M/s Atlas Copco & M/s Sandvik for their inputs during preparation.